WASHINGTON - The fate of the fractious immigration reform bill in the U.S. Senate was shakier Thursday after the chamber voted down amendments and lost supporters.

The bill, which U.S. President George Bush is pushing to pass, has 26 amendments from Democrats seeking to soften some restrictions and Republicans wanting to stiffen them.

Each of the amendments has supporters, most of whom have said their overall votes will be tied to the amendments' passage, and Wednesday saw many fence-sitters fall away as their projects were voted down, The Washington Post reported.

One major amendment rejected was a Republican proposal to require adult illegal immigrants to return to their countries temporarily to qualify for a special new visa, the Post said.

Newcomer Sen. Claire McCaskill, D-Mo., told The New York Times the situation was perplexing.

"I feel like Goldilocks," McCaskill said. "It is either too hot or too cold. It is certainly not just right."